Remove unmaintained expired nvi related ports
2011-05-01 editors/nvi-m17n: Distfile is no more available
2011-05-01 chinese/nvi-big5: Distfile is no more available
2011-05-01 chinese/nvi-euc-cn: Distfile is no more available
2011-05-01 chinese/nvi-euc-tw: Distfile is no more available
2011-05-01 editors/nvi-perl: Distfile is no more available
2011-05-01 japanese/nvi-euc-jp: Distfile is no more available
2011-05-01 japanese/nvi-iso-2022-jp: Distfile is no more available
2011-05-01 japanese/nvi-sjis: Distfile is no more available
2011-05-01 korean/nvi-euc-kr: Distfile is no more available
2011-05-01 korean/nvi-iso-2022-kr: Distfile is no more available

Change PKGDIR from pkg/ to . Also fix places where ${PKGDIR} is spelled out
(many of which are ${PKGDIR}/MESSAGE -> ${PKGMESSAGE} type fixes that
shouldn't have been necessary) and the string "/pkg/" appear.